1. Field of the Invention
The present invention is broadly concerned with vent apparatus of the type used to protect structures (e.g., bag houses, bins, and tanks) from the potentially destructive effects of abnormal pressure conditions therein, i.e., either excessively high or low pressures which could lead to catastrophic failure of the structure. More particularly, the invention is concerned with such vent apparatus having a rupturable burst member normally retained in place by means of a plurality of spaced apart, bendable, non-fragmenting tabs; in the event of an abnormal pressure condition, the tabs bend or buckle without breakage thereof to a member-clearing position allowing the burst member to quickly open to thus vent and protect the structure. The vent tabs are preferably designed as simple, low-mass, torque and load insensitive components which are advantageously out of contact with the protected area within the structure, and provide increased venting efficiency without any rupture or fragmentation of the tabs.
2. Description of the Prior Art
A wide variety of protective devices have been employed in the past to protect confined areas or zones, such as in buildings, manufacturing facilities, tanks, chambers, and other structures. These devices are intended to quickly terminate or interrupt potentially destructive phenomena, such as high pressure conditions conducive to explosions or fires. Generally speaking, venting assemblies are used in this context which include a rupturable member such as a rupture disc or burst panel. Such components are responsive to pressure conditions within a structure to be protected, and are designed to open and vent the structure in the event of an abnormal pressure condition. In some cases, these burst discs or panels fragment upon actuation thereof, but in other instances venting occurs with retention of the disc or panel.
U.S. Pat. No. 5,606,829 describes a mounting assembly for a decompression panel used in aircraft and having blow-out tabs arranged in pairs around the margin of the panel.
The tabs are designed to break in the even of an over- or under-pressure condition, which serves to release the panel.
U.S. Patent Publication 2011/0017315 describes a pressure relief panel for a silo or dust collector having a line of weakness along the panel perimeter, which may be a series of slits that form tabs. The number of slits/tabs controls the pressure differential at which the panel will open.
U.S. Pat. No. 4,385,710 is directed to an emergency pressure relief device for an oil-reserve tank or the like, having a flexible plate secured to a coaming with welds intervals, and flexible sealant between the welds. The length and strength of the welds determines the burst pressure.
U.S. Pat. No. 5,036,632 is directed to a pressure relief panel assembly for tanks, food-processing vessels, and bag houses, having a rupture panel with a hinged blow-out part 22 connected to a restrained part via a plurality of rupture tabs with slits there between. The thickness of the material of the panel and the length of the slits determines the burst pressure.
Other references include U.S. Pat. Nos. 4,385,710, 5,461,831, 5,638,980, 6,367,203, and 7,628,167.
The above-described prior art references do not teach or suggest provision of a vent apparatus with a burst member normally maintained in place by means of non-fragmenting bendable tabs which move to a member-clearing position when the burst member experiences an abnormal pressure condition.